To celebrate the recent launch of Fire Emblem Heroes, Nintendo is giving away 2,222 free gold coins for Super Mario Run. All you have to do to claim them is log in and tap on the gift box up in the top right hand corner of your kingdom. Despite how it may first appear, there are absolutely no strings attached, as you don't need to download Fire Emblem Heroes or pay the $10 to unlock all the Super Mario Run courses to receive the gift. With interest in Super Mario Run waning of late, the whole thing is primarily designed to get you to log back into the game and start playing again.
According to Nintendo president Tatsumi Kimishima the game has been downloaded 78 million times on iOS devices (the Android version still isn't out, and is due in March) and "more than 5%" have paid the $10 for the full version – so that's roughly 4 million people.